Uther’s union with Igraine is the founding deception behind Arthur’s birth: with Merlin’s aid, Uther takes on the likeness of Igraine’s husband and enters Tintagil, and Arthur is conceived before Igraine knows who has come to her. The episode joins political desire to magical disguise, then makes the child’s secret upbringing part of the bargain that follows.

Causes and Bargain

During Uther’s war against the Duke of Cornwall, Ulfius reports that he has found Merlin. Uther welcomes the magician and tells him of his desire. Merlin promises to bring it about, but first secures Uther’s oath on the four Evangelists: once Igraine has been won, any child born of the union must be given to Merlin to nourish as he chooses. Uther agrees, binding his private wish to a future arrangement for the child.

Merlin’s plan depends on mistaken identity. He instructs Uther to appear as the Duke, Ulfius to resemble the Duke’s knight Sir Brastias, and Merlin himself to take the likeness of Sir Jordanus, another of the Duke’s knights. Uther is warned not to ask many questions and to claim illness before going to bed. The transformation is presented as a means of entering Tintagil under cover of the Duke’s identity, not as an open courtship between Uther and Igraine.

The Night at Tintagil

The Duke notices Uther leaving the siege of Terrabil and rides out by a postern gate to attack the king’s host. He is killed before Uther reaches Tintagil. Uther arrives at the castle more than three hours after the Duke’s death and finds Igraine there; the narrative thus places the disguised encounter after the husband has already died, though Igraine does not know this at the time.

Before daybreak, Merlin returns and tells Uther to make ready to leave. Uther kisses Igraine and departs in haste. When Igraine learns that the Duke was dead before the man who had appeared in his likeness came to her, she wonders who the visitor could have been. She mourns privately and keeps silent. The secrecy of the encounter rests on the gap between what Igraine experienced—the apparent return of her husband—and what the reader is later told about Uther’s disguise and the Duke’s death.

Disclosure and Marriage

Within half a year, while Igraine is pregnant, Uther asks her whose child she carries. Igraine explains that on the night of her husband’s death a man resembling him in speech and appearance came to Tintagil with two knights resembling Brastias and Jordanus. She says she welcomed him as she would her husband and swears to the truth of her account.

Uther admits that he was the visitor and that he came in the likeness of the Duke on Merlin’s counsel. Igraine then rejoices at learning that Uther is the child’s father. After the Duke’s death, Uther’s barons have already urged an agreement between the king and Igraine; Uther entrusts the negotiation to Ulfius. The barons support the proposed marriage, and Uther and Igraine marry in the morning with public rejoicing. The union therefore moves from an undisclosed encounter to a recognized royal marriage, but only after the identity concealed by Merlin’s magic is made known.

Arthur’s Birth and Secret Upbringing

Merlin reminds Uther that the child must be provided for, invoking the earlier agreement. He names Sir Ector as a trustworthy lord to raise the child and directs that Ector’s wife nurse the king’s child in place of her own. Uther accepts the arrangement and summons Ector, who promises to care for the child and receives rewards from the king.

When Igraine gives birth, Uther orders two knights and two ladies to carry the child, wrapped in cloth of gold, to a poor man they are to meet at the castle’s postern. The child is instead delivered to Merlin, who takes him to Sir Ector. An unnamed holy man christens him Arthur, and Ector’s wife nurses him. The royal child’s birth is thus followed immediately by concealment and fosterage, fulfilling Merlin’s condition and separating Arthur’s early upbringing from the circumstances of his conception.

Narrative and Historical Framing

The account gives the episode a consequential place in the history of Arthur’s kingship: Uther’s deception leads to Arthur’s conception, while Merlin’s intervention shapes the child’s upbringing before Arthur can know his parentage. The episode’s causal chain—desire, oath, disguise, disclosure, marriage, and secret fosterage—makes the founding of the royal line inseparable from concealment.

The book’s later editorial discussion distinguishes such legendary history from verifiable geography and chronology. It says that Malory’s historical chapters draw mainly on Geoffrey of Monmouth’s Historia Brithonum, while much also appears in romances, and declines to settle whether Arthur actually existed. That framing presents the story of Uther and Igraine as part of the romance’s heroic history, rather than establishing the episode as independently verified fact.